Asphalt pavers include a hopper for receiving paving material and a conveyor system for transferring the paving material from the hopper for discharge on the roadbed. Screw augers spread the material on the roadbed in front of a floating screed, which is connected to the paving machine by pivoting tow or draft arms. The screed functions to format and compact the paving material distributed by the augers, ideally leaving the finished road with a uniform, smooth surface.
Such machines may be propelled by using rubber wheels that are disposed on opposite sides of the machine. Typical rubber wheeled machines have front steerable or steered wheels and a mechanical differential that drives the rear driven wheels. However, this type of machine cannot effectively control wheel slip by directing power to only one wheel.
A second alternative drive system is to independently drive each driven wheel. The independent drive requirement creates the problem of controlling the relative speed of each wheel to appropriately follow the turn path of the front steered wheels, while providing full power with minimal slip to each wheel. A closed loop electronic control system is one method to provide the required control. However, one difficulty of designing such a control is defining the control relationship between the right and left driven wheels so that the individual operating characteristics of an individual machine are taken into account.
The present invention is directed to resolve these problems by determining the control relationship between the right and left driven wheels in order to follow the path of the steered wheels. Additionally, the present invention modifies the control relationship to provide for enhanced turning capabilities by overdriving the driven wheels.